This invention relates to a radial piston pump or motor of the type comprising a pintle valve having a rotor rotatably mounted thereon and a plurality of pistons secured on the rotor and disposed circumferentially thereabout. A closed cylinder is reciprocally mounted on the end of each of the pistons for communicating pressurized fluid to an outlet of the pump upon rotation of the rotor. The rotor is eccentrically mounted relative to a cylindrical chamber defined in a housing of the pump and the cylinders are maintained in sliding bearing contact with surface portions defining the inside diameter of the chamber.
Such pumps may each comprise a plurality of separate passages for communicating an inlet to the pump with an inlet side of the pintle valve. The passages may give rise to cavitation and related problems, particularly when the pump is run at high speeds in excess of its pumping capacity.